MEC1322 Datasheet, PDF (291/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
26.5 Power, Clocks and Reset
This section defines the Power, Clock, and Reset parameters of the block.
26.5.1 POWER DOMAINS
TABLE 26-2: POWER SOURCES
Name
VCC1
26.5.2 CLOCK INPUTS
Description
This power well sources the registers and logic in this block.
TABLE 26-3: CLOCK INPUTS
Name
48 MHz Ring Oscillator
26.5.3 RESETS
Description
This clock signal drives selected logic (e.g., counters).
TABLE 26-4: RESET SIGNALS
Name
VCC1_RESET
Description
This reset signal resets all of the registers and logic in this block.
26.6 Interrupts
This section defines the Interrupt Sources generated from this block.
TABLE 26-5: INTERRUPTS
Source
Fan Fail/Spin Status Interrupt
Fan Stall Status Interrupt
Description
The DRIVE_FAIL & FAN_SPIN bits in the Fan Status Register are logi-
cally ORed and routed to the FAIL_SPIN Interrupt
The FAN_STALL bit in the Fan Status Register is routed to the
FAN_STALL Interrupt
26.7 Low Power Modes
The RPM-PWM Interface may be put into a low power state by the chip’s Power, Clocks, and Reset (PCR) circuitry.
26.8 Description
This section defines the functionality of the block.
26.8.1 GENERAL OPERATION
The RPM-PWM Interface is an RPM based Fan Control Algorithm that monitors the fan’s speed and automatically
adjusts the drive to maintain the desired fan speed. This RPM based Fan Control Algorithm controls a PWM output
based on a tachometer input.
26.8.2 FAN CONTROL MODES OF OPERATION
The RPM-PWM Interface has two modes of operation for the PWM Fan Driver. They are:
1. Manual Mode - in this mode of operation, the user directly controls the fan drive setting. Updating the Fan Driver
Setting Register (see Section 26.9.1, "Fan Setting Register") will update the fan drive based on the programmed
ramp rate (default disabled).
• The Manual Mode is enabled by clearing the EN_ALGO bit in the Fan Configuration Register (see Section 26.9.3,
"Fan Configuration 1 Register").
• Whenever the Manual Mode is enabled the current drive settings will be changed to what was last used by the
RPM control algorithm.
• Setting the drive value to 00h will disable the PWM Fan Driver.
• Changing the drive value from 00h will invoke the Spin Up Routine.
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DS00001719D-page 291